NULL Pointer Dereference Affecting kernel-headers package, versions <0:6.1.127-135.201.amzn2023


Severity

Recommended
high

Based on Amazon Linux security rating.

Threat Intelligence

EPSS
0.04% (6th percentile)

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  • Snyk IDSNYK-AMZN2023-KERNELHEADERS-9524858
  • published27 Mar 2025
  • disclosed19 Jan 2025

Introduced: 19 Jan 2025

CVE-2025-21637  (opens in a new tab)
CWE-476  (opens in a new tab)

How to fix?

Upgrade Amazon-Linux:2023 kernel-headers to version 0:6.1.127-135.201.amzn2023 or higher.
This issue was patched in ALAS2023-2025-823.

NVD Description

Note: Versions mentioned in the description apply only to the upstream kernel-headers package and not the kernel-headers package as distributed by Amazon-Linux. See How to fix? for Amazon-Linux:2023 relevant fixed versions and status.

In the Linux kernel, the following vulnerability has been resolved:

sctp: sysctl: udp_port: avoid using current->nsproxy

As mentioned in a previous commit of this series, using the 'net' structure via 'current' is not recommended for different reasons:

  • Inconsistency: getting info from the reader's/writer's netns vs only from the opener's netns.

  • current->nsproxy can be NULL in some cases, resulting in an 'Oops' (null-ptr-deref), e.g. when the current task is exiting, as spotted by syzbot [1] using acct(2).

The 'net' structure can be obtained from the table->data using container_of().

Note that table->data could also be used directly, but that would increase the size of this fix, while 'sctp.ctl_sock' still needs to be retrieved from 'net' structure.

CVSS Base Scores

version 3.1